The present embodiments relate to medical imaging. In particular, imaging with a nuclear probe is provided.
Diagnostic medical modalities, such as computed tomography (CT), magnetic resonance (MR), and ultrasound acquire detailed images. The images depict anatomical structures, such as location of internal organs and tumors. Other modalities, such as positron emission tomography (PET) and single positron emission computed tomography (SPECT), may visualize functional changes or information. PET and SPECT may show areas of cancerous growth or other operation of anatomy, but with less or no details about the surrounding anatomy.
These imaging modalities may not be usable during a surgical procedure. For 3D tomography scanning procedures, a patient lies on a motorized bed which moves inside a doughnut-shaped image acquisition device. The device limits surgical access. Scanning with such large complex systems may be expensive.
In nuclear medicine, hand-held nuclear activity devices, such as a gamma probe or a beta probe, are capable of detecting the uptake of injected tumor-seeking radiopharmaceuticals. Gamma probes, for example, are used in parathyroid and sentinel lymph node surgery, where the gamma probes provide an audible signal to locate regions where injected radionuclides are present. The locations detected with a gamma probe may be visualized rather than just relying on an audible signal. A tracking system measures the position of the gamma probe while acquiring data to compute the images. The user manually positions the gamma probe against the patient's skin for detection. Such images may then be fused with image data coming from other detectors. For example, images produced with an optically-tracked gamma probe are fused together with images from a video camera calibrated into the same coordinate space. The resulting fused image shows the location of sentinel lymph nodes overlaid onto the patient's skin, providing guidance to surgeons. However, optical tracking of the hand-held probe requires calibration based on marker positions and suffers from limited accuracy. Reconstruction from the acquire projection data is complicated by the manual positioning of the gamma probe. The reconstructed image may have inadequate quality, requiring the process to be performed again. Since radionuclides are involved, repetition may be undesired.